Summary Mosby’s Pathophysiology- Alterations of Hematologic Function I- Updated version

Mosby’s Pathophysiology- Alterations of Hematologic Function I Lesson Information Purpose • The purpose of this online course is to assist healthcare professionals to understand the pathophysiology of common diseases and disorders, the underlying causes, clinical manifestations, and diagnostic testing, and current treatment. Abstract • This lesson is an overview of hematologic function. It presents information on anemias and other blood cell abnormalities. Introduction • The hematologic system is responsible for numerous vital body functions, including the: o Delivery of oxygen to tissues o Provision of cells for the inflammatory and immune responses o Control of bleeding • Pathologic alterations of hematologic function involve erythrocyte (red blood cell) production and function, and they lead to many common and serious pathophysiologic conditions. • In this lesson, you will explore alterations in hematologic function. An understanding of these processes is essential to the assessment and care related to this common and important group of diseases. Learning Objectives • After completion of this lesson, you should be able to: o Identify the common classifications and clinical manifestations of anemia. o Compare and contrast the risk factors, pathophysiology, and evaluation of macrocytic, normocytic and microcytic anemias. o Recognize the pathophysiology and assessment of myeloproliferative erythrocyte disorders. Altered Erythrocyte Function: Definition of Anemias • Anemia is a reduction in the total mass of circulating erythrocytes and is diagnosed by a decrease in the quality or quantity of hemoglobin. The causes of anemia are: o Altered erythrocyte production o Blood loss o Increased erythrocyte destruction o And/or a combination of all three of the above Altered Erythrocyte Function: Classification of Anemias • Anemias are classified by their causes or by the changes that affect the erythrocytes' size, shape, or substance. The most common classification of anemias is based on cell size and hemoglobin content. Terms that end with "cytic" refer to cell size. Those that end with "chromic" refer to hemoglobin content. Morphologic Classification of Anemias Definition Primary Cause Macrocytic- Large, abnormally shaped • Congenital or acquired deficiency of normochromic erythrocytes and a normal intrinsic factor (IF); genetic disorder of anemias hemoglobin concentration deoxyribonucleic acid (DNA) synthesis • Dietary folate deficiency Microcytic- Small, abnormally shaped • Chronic blood loss; dietary iron hypochromic erythrocytes and a reduced deficiency, disruption of iron metabolism anemias hemoglobin concentration or iron cycle • Congenital dysfunction of iron metabolism in erythroblasts, acquired dysfunction of iron metabolism as a result of drugs or toxins • Congenital genetic defect of globin synthesis Normocytic- Destruction or depletion of • Depressed stem cell proliferation, normochromic normal erythroblasts or resulting in bone marrow aplasia anemias mature erythrocytes • Acute or chronic hemorrhage that stimulates increased erythropoiesis, which eventually depletes body iron • Any condition that increases erythrocyte fragility • Congenital dysfunction of hemoglobin synthesis • Chronic infection or inflammation; malignancy • Additional terms describing erythrocytes found in some anemias are anisocytosis